1. Technical Field
The present invention relates to a liquid crystal device capable of switching display modes of a wide viewing angle and a narrow viewing angle and an electronic apparatus having the same.
2. Related Art
Recently, a liquid crystal device has come into widespread use in electronic apparatuses such as a mobile phone, a portable information terminal, and a computer display. In such a liquid crystal device, a wide viewing angle characteristic is necessary when many people look at a displayed image in various directions, and a narrow viewing angle characteristic is necessary when it is desired not to show the displayed image to the people around a user.
For this reason, a liquid crystal device capable of switching a display mode between a wide viewing angle and a narrow viewing angle was proposed (for example, refer to JP-A-2007-79525, JP-A-2007-178736, JP-A-2007-178738, JP-A-2007-178739, and JP-A-2003-233074).
In JP-A-2007-79525, there is disclosed a vertical alignment or twisted nematic liquid crystal display device having a configuration in which RGB color pixels and a W pixel are provided as one unit and the RGB color pixels and the W pixel have different viewing angle characteristics. By adopting such a configuration, a wide viewing-angle display mode and a narrow viewing-angle display mode can be switched.
In JP-A-2007-178736, JP-A-2007-178738 and JP-A-2007-178739, there is disclosed a FFS (Fringe Field Switching) mode liquid crystal display device having a configuration in which RGB pixels and viewing-angle control pixels are provided and each viewing-angle control pixel is brought under alignment control such that the liquid crystal molecules tilt vertically or horizontally. By adopting such a configuration, an angle of view can be controlled in vertical and horizontal directions. In the liquid crystal display device, a control voltage is applied to the viewing-angle control pixels through viewing-angle control lines separated from the RGB pixels. In this manner, it is possible to tilt the liquid crystal molecules vertically or horizontally, thereby controlling the viewing angle.
In a liquid crystal display device disclosed in JP-A-2007-178738, each viewing-angle control pixel is not connected to a TFT (Thin Film Transistor) as a switching element, and is directly connected to a signal line, and a voltage signal is applied to all the viewing-angle control pixels when it is intended to conceal display information on a whole display screen. In this case, display unevenness can also be suppressed by adjusting a signal center of the viewing-angle control pixels to coincide with a common voltage of the RGB pixels through a unit for adjusting a viewing-angle control voltage.
In JP-A-2003-233074, there is disclosed a liquid crystal display device configured such that a fixed pattern irrespective of a display screen is visible when the display is viewed from directions other than the front direction. By adopting such a configuration, displayed contents can be protected from being seen by another person.
The recent liquid crystal display device is classified into a vertical electric field mode and a horizontal electric field mode in accordance with an electric field direction. The vertical electric field mode is a mode of generating an electric field (vertical electric field) between an upper substrate and a lower substrate on which electrodes are formed, and the liquid crystal display device disclosed in JP-A-2007-79525 is an example of this mode. On the other hand, the horizontal electric field mode is a mode of generating an electric field (horizontal electric field) in a direction substantially parallel to a side of one substrate, on which electrodes are formed, of a pair of substrates, and the FFS mode liquid crystal display devices disclosed in JP-A-2007-178736, JP-A-2007-178738, and JP-A-2007-178739 arm examples of this mode.
However, a problem arises in that the horizontal electric field mode liquid crystal display device is inferior to the vertical electric field mode liquid crystal display device of the in viewing-angle control effect.